If there are two paper printers, please adjust them to A3 and A4 respectively. Print-Properties-Select the next paper size. Two cartons should only increase the number of papers, and should be set when printing! The printer doesn't seem to have the function of setting two kinds of paper. What kind of printer is used upstairs? You should put the commonly used paper in the paper box, and others that are not commonly used can be put in the front door or behind the printer (some printers can also put the paper in the back first). As far as I know, all printers of Dell, Hewlett-Packard and Samsung are sold separately from the second box, so there should be no such function.